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#include "../command.h"
#include <stdio.h>
#include <string.h>
struct Flags {
int count;
bool lines;
bool print_headers;
bool dont_print_headers;
};
static void head_file_lines(FILE* file, struct Flags* flags) {
size_t len = 0;
char* line = NULL;
int count = flags->count;
while(count > 0 && getline(&line, &len, file) != -1) {
printf("%s", line);
count--;
}
free(line);
fclose(file);
}
static void head_file_chars(FILE* file, struct Flags* flags) {
char c;
int count = flags->count;
while(count > 0 && (c = getc(file)) != EOF) {
putchar(c);
count--;
}
fclose(file);
}
static void help() {
printf("Usage: head [OPTIONS] [FILE]...\n\n");
printf("Print first 10 lines of FILEs (or stdin)\n");
printf("With more than one FILE, precede each with a filename header.\n\n");
printf("\t-c [+]N[bkm]\tPrint first N bytes\n");
printf("\t-n N[bkm]\tPrint first N lines\n");
printf("\t\t\t(b:*512 k:*1024 m:*1024^2)\n");
printf("\t-q\t\tNever print headers\n");
printf("\t-v\t\tAlways print headers\n");
exit(EXIT_SUCCESS);
}
static char* next_arg(int argc, char** argv, int index) {
if (index >= argc) {
error("error: expected another argument after option");
}
return argv[index];
}
static void print_header(char* path, struct Flags* flags, bool many) {
if (flags->dont_print_headers) return;
if (!many && !flags->print_headers) return;
if (streql("-", path)) {
printf("\n==> standard input <==\n");
} else {
printf("\n=>> %s <==\n", path);
}
}
static void head_file(char* path, struct Flags* flags, bool many) {
FILE* file = get_file(path, "r");
print_header(path, flags, many);
if (flags->lines) {
head_file_lines(file, flags);
} else {
head_file_chars(file, flags);
}
}
COMMAND(head) {
struct Flags flags;
flags.count = 10;
flags.lines = true;
flags.print_headers = false;
flags.dont_print_headers = false;
int start = 0;
for (int i = 0; i < argc; i++) {
if (!prefix("-", argv[i])) break;
if (streql(argv[0], "--help")) help();
start++;
int i_s = i;
for (size_t j = 1; j < strlen(argv[i_s]); j++) {
char c = argv[i_s][j];
switch(c) {
case 'c': {
start++;
flags.lines = false;
char* arg = next_arg(argc, argv, ++i);
long int bkm = get_blkm(arg);
if (bkm < 1) {
error("error: bkm cannot be less than 1");
}
flags.count = bkm;
break;
}
case 'n': {
start++;
flags.lines = true;
char* arg = next_arg(argc, argv, ++i);
long int bkm = get_blkm(arg);
if (bkm < 1) {
error("error: bkm cannot be less than 1");
}
flags.count = bkm;
break;
}
case 'q':
flags.dont_print_headers = true;
break;
case 'v':
flags.print_headers = true;
break;
default: {
error("error: unknown option -%c", c);
}
}
}
}
int count = argc - start;
if (count < 1) {
head_file_lines(stdin, &flags);
return EXIT_SUCCESS;
}
if (count == 1) {
head_file(argv[start], &flags, false);
return EXIT_SUCCESS;
}
for (int i = 0; i < count; i++) {
head_file(argv[start + i], &flags, true);
}
return EXIT_SUCCESS;
}
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